Well, we don't know exactly what the Exxon deal would have delivered, but I have to say I'm a little surprised at the outcome. I would have thought that the economics (and time) of a third train at Exxon would have given them a considerable leg up in the negotiations.
But I've also said several times that these negotiations have a habit of moving according to their own dynamics. I have a feeling the large stake in the LNG plant is the most important factor that swayed it for IOC, or perhaps there was something in the Exxon deal that they didn't like, perhaps a complication with the existing partners, or just a better feel with Total. But I speculate as well 
And it isn't terribly important anymore, unless the losers from the bidding won't take no for an answer. And they can indeed sit back for a while and let the drilling derisk further. One or two new significant finds, which is well within the realm of possibilities (albeit by no means a given), well, one would really think that IOC would become a very attractive take-over candidate.